Indian Journal of
Engineering & Materials Sciences

 

VOLUME 8

NUMBER 6

DECEMBER 2001

 

CONTENTS

 

Engineering

 

Turbulence measurements in three-dimensional wall jets on convex cylindrical surfaces

313

        B H Lakshmana Gowda & V S B Durbha

 

 

Investigation of soil engineering properties for safe design and construction of the iron ore failing dam

318

        M K Ghose & P K Sen

 

 

Development of soft computing models for data mining

327

        S N Sivanandam, A Shanmugam, S Sumathi & K Usha

 

 

Diagonal cracks of structural concrete beams under short-term load with unloading

341

        Terezia Nurnbergerova, Martin Krizma & Jan Hajek

 

 

Viscous heating in free convection along a plate in presence of magnetic fields

347

        S S Tak & Rohit Kumar Gehlot

 

Materials Science

 

Phase identification and electrochemical impedance studies on the ternary system (CdI2)a [(Ag2O).(MoO3)]100–a (20 £ a £ 80)

352

        S Austin Suthanthiraraj & A C Ganeshkumar

 

 

Casting and characterisation of Al-1.2 Si-Sn alloys

357

        J P Pathak, P Panigrahi & A K Ghose

 

 

Microwave related properties of fritless Ag thick film metallisation and effect of long-term air exposure

366

        Vjaya Puri & S V Rane

 

 

Spectroscopic investigation of BiSeI, SbSeI compounds and BiSbSxSe1-xI solid solutions

373

        G Kanchana & D Arivuoli

 

 

Optical waveguiding in vacuum deposited polyaniline thin films

377

        Sudhir Kumar Sharma, V K Sharma, A Kapoor, S C K Misra & K N Tripathi

 

Spectroscopic studies on curing of novolac epoxy resin — Polyamide and polyamine hardener systems in presence of polysulphide

 

381

        P S Makashir, N T Agawane, R R Mahajan & J P Agrawal

 

Annual Index

386

 

 


Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 313-317

 

 

Turbulence measurements in three-dimensional wall jets on

convex cylindrical surfaces

 

B H Lakshmana Gowda & V S B Durbha

 

The variation of maximum values of the turbulent normal and shear stresses in three-dimensional wall jets on convex cylindrical surfaces are described here. The curvature parameter, b/R, where b is the half width and R is the radius of curvature, is varied from 0.01 representing mild convex curvature to 1 (strong curvature). The results indicate that the maximum values of normal stresses increase with curvature parameter. The shear stresses also increase with curvature.

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 318-326

 

Investigation of soil engineering properties for safe design and

construction of the iron ore tailing dam

M K Ghose  & P K Sen

The need for the disposal of iron ore tailings in an environmentally friendly manner is of great concern to the mining authority. It is envisaged that by the end of this century, India would be generating 27 Mt of iron ore tailings per year for which safe disposal by way of containment in tailing ponds are needed. For the safe design and construction of the tailing dam as well as for the augmentation of its existing capacity, detailed field and laboratory investigations are described here. To augment capacity of the tailing pond, raising height of the existing tailing dam in two stages of 5 m each is conceived. Samples have been collected from soil and tailing borrow areas by making pits up to 2 m depth. Bore holes have been drilled and seismic studies are carried out to establish the depth of bed and its thickness. Standard penetration test (SPT) and permeability test have also been conducted. Undisturbed soil samples along with disturbed samples have been collected and existence of ground water table is noted. Details of the bore log data and in situ test results have been discussed and laboratory tests are conducted on the collected samples. Bulk geology and foundation treatment, construction material and design data used, method of stability analysis and software used for stability analysis are also described.

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 327-340

 

Development of soft computing models for data mining

S N Sivanandam, A Shanmugam, S Sumathi & K Usha

The increasing amount and complexity of today’s data available in science, business, industry and many other areas creates an urgent need to accelerate discovery of knowledge in large databases. Such data can provide a rich resource for knowledge discovery and decision support. To understand, analyze and eventually use this data, a multidisciplinary approach called data mining has been proposed. Technically, data mining is the process of finding correlation or patterns among dozens of fields in large relational databases. Pattern classification is one particular category of data mining, which enables the discovery of knowledge from very large databases (VLDB). In this paper, mining the database through pattern classification has been done by utilizing two important mining tools called K-Nearest Neighbour algorithm and Decision trees. The K-Nearest Neighbour (K-NN) is the popularly used conventional statistical approach for data mining. K-NN is a technique that classifies each record in a data set based on a combination of the classes of K-records most similar to it in a historical data set. The fuzzy version of K-NN, crisp and fuzzy versions of nearest prototype classifiers have also been proposed. Decision tree is one of the best machine learning approaches for data mining. A decision tree is a predictive model that as its name implies, can be viewed as a tree. Briefly, decision trees are tree shaped structures that represent sets of decisions. These decisions generate rules for classification of a data set. Classification and Regression Tree (CART), ID3 are the two decision tree methods used in this paper. The classification rules have been extracted in the form of IF THEN rules. The performance analysis of K-NN methods and tree-based classifiers has been done. The proposed methods have been tested on three applications such as land sat imagery, letter image recognition and optical recognition of hand written digits data. The simulation algorithms have been implemented using C++ under UNIX platform.

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 341-346

 

Diagonal cracks of structural concrete beams under short-term load with
unloading

Terezia Nürnbergerová, Martin Križma & Ján Hájek

 

Characteristics of the process of diagonal cracking have been studied and their evaluation based on the experimental investigation of reinforced and prestressed concrete beams subjected to short term load with unloading has been carried out. The relations between shear deformations and the characteristics of cracking are explained in the paper. The relationship between the reversible part of diagonal crack opening density and the diagonal crack opening density immediately before unloading is also presented.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 347-351

 

Viscous heating in free convection along a plate in presence of magnetic field

 

S S Tak & Rohit Kumar Gehlot

The steady free convection boundary layer flow along a semi-infinite isothermal vertical plate in presence of transverse magnetic field, taking the frictional heat into account, is reported here. The governing equations have been solved by taking series expansion of stream function and the temperature function in powers of Brinkman number (Br). The resulting ordinary non-linear coupled differential equations with boundary conditions have been solved numerically using computer by Newton's shooting technique. The velocity and temperature profiles are drawn for different values of Prandtl number, magnetic field parameter and Brinkman number. The expressions for the skin-friction and Nusselt number have been obtained and the numerical values of , which correspond to local skin-friction and rate of surface heat transfer, are also described. The effects of magnetic field, Prandtl number and frictional heating have been discussed in detail.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 352-356

 

 

Phase identification and electrochemical impedance studies on the ternary system (CdI2)a [(Ag2O).(MoO3)]100-a (20£ a£ 80)

S Austin Suthanthiraraj & A C Ganeshkumar

An experimental investigation concerning the phase characterization through X-ray Diffraction (XRD) and electrochemical impedance analysis of the ternary system (CdI2)a [(Ag2O).(MoO3)]100-a (20 £ a £ 80) is presented in detail. The observed XRD data suggest the formation of several polycrystalline phases including cubic g–AgI in certain compositions. The complex impedance studies carried out in the frequency range 20 Hz-1 MHz and over the temperature range 294-442 K, have revealed that the best conducting composition, namely 45%(CdI2)-55%(Ag2O.MoO3), would exhibit a silver ionic conductivity of 4.57x10-5 Scm–1 at 299 K.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 357-365

 

Casting and characterisation of Al-1.2Si-Sn alloys

 

J P Pathak, P Panigrahi & A K Ghose

The aim of this investigation was to disperse tin uniformly and discontinuously in Al-l.2Si alloy matrix and assess the properties of as cast Al-1.2Si-Sn alloy at room temperature. A few compositions of Al-1.2Si-Sn alloys were prepared by impeller mixing and bottom discharge chill casting technique. Microstructure of the as cast alloys was studied under optical microscope. Mechanical properties of the cast products were evaluated at room temperature. Wear characteristics under dry sliding were assessed, employing pin-on-disc wear test machine. Uniform and discontinuous dispersion of tin in Al-1.2Si alloy was observed. Tin decreased the strength of Al-1.2Si alloy but enhanced the percentage elongation and wear resistance.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 366-372

 

Microwave related properties of fritless Ag thick film metallisation and effect of long-term air exposure

Vijaya Puri & S B Rane

Investigations on the laboratory-formulated fritless silver thick film metallisation for use at microwave frequencies is reported here. The reflectometer method has been used to measure the microwave (8-18 GHz) transmittance and reflectance of these films deposited by screen printing onto 96% alumina substrates. The effects of firing temperature, composition and long term air exposure on the microwave properties and d.c. resistivity are also reported. In the X-band frequency, composition and firing temperature-dependent transmittance and reflectance of metallisation are obtained whereas at Ku-band, the above properties are to a large extent independent of these factors. The microwave conductivity as well as the d.c. resistivity are found to increase on aging. The results indicate the utility of these fritless Ag thick film metallisation up to 18 GHz. Firing temperature-independent properties provide substantial energy saving and increased furnace life as the films fired at 800°C compare well with those fired at 900°C especially at higher frequencies.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 373-376

 

 

 

Spectroscopic investigation of BiSeI, SbSeI compounds and BiSbSxSe1-xI solid solutions

G Kanchana & D Arivuoli

The compounds such as SbSeI, BiSeI and solid solutions of BiSbSxSe1-xI (x = 0.2 to 0.8 mol fractions) are grown from vapour by chemical vapour transport method. The IR and Raman spectra were recorded in the range 600-50 cm-1. The IR spectra reveal that the frequency modes are sensitive to selenium substitution and the Raman spectra show that the bands below 200 cm-1 are halogen sensitive.

 

 

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 377-380

 

Optical waveguiding in vacuum deposited polyaniline thin films

 

Sudhir Kumar Sharma, V K Sharma, A Kapoora, S C K Misra & K N Tripathi

 

Polyaniline thin films prepared by vacuum deposition of polyaniline powder, have been found to exhibit good optical waveguiding properties. The waveguide parameters, refractive index, propagation loss and depth, are found to be strongly affected by doping of these thin films. A detailed study of the optical absorption, effective refractive index, optical propagation losses and propagation depth for these thin films has been carried out using the integrated optics techniques. Vacuum deposited polyaniline thin film planar optical waveguides exhibit low optical attenuation and have optical refractive index 1.590 and excellent transmission in the wavelength range 350-650 nm, which make this polymer promising for integrated optical devices.

 

 

Indian Journal of Engineering & Materials Sciences

Vol. 8, December 2001, pp. 381-385

 

 

Spectroscopic studies on curing of novolac epoxy resin—Polyamide and polyamine hardener
systems in presence of a polysulphide

 

P S Makashir, N T Agawane, R R  Mahajan & J P Agrawal

Novolac epoxy resins have recently been reported for inhibition of hydroxy terminated polybutadiene (HTPB) based composite propellants and their elongation has been improved by the incorporation of some flexibilizers. In the present investigation, curing behaviour of a novolac epoxy resin (Dobeckot E4) by hardeners (polyamide EH 411 and polyamine H 758) in conjunction with a polysulphide flexibilizer has been studied using infrared (IR) spectroscopy. It is observed that the rate of curing of Dobeckot E4 by hardeners such as hardener EH411 and hardener H 758, is higher as compared to polysulphide flexibilizer LP-33. Further, rate of curing of epoxy resin by hardeners such as EH411 and H758 enhances in the presence of flexibilizer LP-33. The curing studies by infrared (IR) spectroscopy suggest that hardeners EH411/H758 react with epoxy ring of epoxy resin and as a result, epoxy ring opens while curing. Similarly, - SH group of polysulphide flexibilizer LP-33, reacts with the epoxy ring of resin and opens it as curing progresses and thus enhances the rate of curing of epoxy resin in conjunction with hardeners EH411/H758. This is also supported by the gel time and exotherm peak temperature data.